Radio signaling apparatus



M. LATOUR RADIO SIGNALING APPARATUS Filed Aug. 19, 1921 sept. 20,1927.1,643,075

vwamoz MARlus LATOUR @5% W' wmoa/Q Mm 10 tion reference is made to the.l drawing in which Fig. .1\ is -a diagrarmnatic 5Piemme sept. 2o, i927.

-UNITED -sTATEs -v 1,643,015 l'PATENT oFl-IcE.

HABIUS LATOUR, or ARIs, FRANCE, AssIGNOR To LATOUR CORPORATION, 02mmCITY,` NEWJERSEY, .A CORPORATION 0F DELAWARE.

Application filed August 19,1921, Serial No. 493,668, and in France-July30, 1917.

o RADIO SIGNALNG 'APrARATUs (GRANTED man TRE rnovrsrons or THE AcT orvnamur a, v1921, 41 STAT. 12,1313.)A

This 'invention has-references to anv .provement 1n or modlficatlon 'ofthe inven- Ation claimed in my prior application, U. S.4

Serial No. -209,269, now Patent No. 1,405,523,

'5 and relates Ato `the adaptation of the amplifyingarrangementdescribedv in .the above specification to the reciprocalconnections for -telephonietransmission;`

For a complete description of my invenaccompanymg showing of a two valveamplifying arrangement according to myl invention; Fig.- 1a is amodification of Fig. l showing the use of 'transformers in `theamplifier-inlet and outlet; Fig.- 2 shows one form, of the exittransformenused in Fig.'1;'Fig.;3 shows a modification of the'exittransformer; Fig. 4.shows a stillfurther modification of the zo exittransformer.

,imwinding of the transformer -T1 In Figure 1 this adaptation isillustrated.-

As was set forth in the main application, Ithe amplifying arrangementcomprises lamp relays 1, comprising plates2, grids 3 and' filaments 4heated by means lof the source 5.

l `The plate circuits are supplied with current by'the battery P. Thecurrent to be amplified is led into the primary of the transformer T1,the secondary of which supplies current 3* to the grid-filamentcircuitof the first lamp.

' 'The -transformer T2 serves to transmit the amplified current to thesecond lamp. The current as amplified is supplied in series to thetelephone line L2,by the secondaries S1,

u S2, S3, S4 ofthe transformer T3. The primary of the transformer Tlisconnected'as .ashunt to the line between the points a, b, whichrepresent the mid points of Ithe'secondaries S2, S2, S3, S2. l

In order that there may be no. singing butV good amplification,nevertheless it 1s necessary to equalize, as far as possible, the-1mpedances of the eastern and western sldes of the line, L L2. Thisisfeffected by put- 5 ting resistances, inductances and capaclties ofsuitable values (or any combinations of I these elements) series or as ashunt on'the eastern or western side (or on both at the N prisessfourwindingsv S13, S23', S32, Sgshunt.-

same time) of the line L1, L2. The precautions already indicated in Vtheparent specification and the .additions therev of the earth,- etc.) arealso taken.

In the event ofthe asymmetry of the'impedances on the eastern or westernsides of the'line being too great, different numbers. of turns mightJ-beadmitted for the'secondariesSl, S2, S3 and` S3, the side of smaller-Vlmpedance requiring ,the smaller numberof turns.

'Experiencelshows that 'for the -construction of the transformers T3good 'results are -obtained by constructing the secondaries S3, S4 andS2, S3 of coils located on both sidesA of .the primary, in such a waythatthe pri- C mary o trai position. The secondaries 2, S4 and- S2, S3are wound together, the winding being effected with two wires in hand.In Figure-2 the exitltransformer T8 is the transformer T3Occu ies acenshown alone. An adjustable resistanceR has the primary of thistransformer, and adjustable 'resistances R,l and R2 connecteddiagponally to thev terminals ofthe vsecondaries been shown as a shuntto thee terminals of S1, S2, S3, S4 of the same transformer. The lobject of the arrangement `of these resistances 1s to prevent singing bytending to establish automatic balancing' of `the eastern western sidesof the line L1, L2.

It. will -in fact be observed that only an asymmetry can; make amplifiedcurrent flow 1n the diagonal resistances R1 and R2. The

asymmetry therefore tends to dam the am- 3 plification when' occasionarises, t at is to say, when this asymmetry .would -tend to causesinging. Instead of thel resistance R, or 1n series with it, a testingreceiver might 'be\jnserted, which would enable the working of thetelephone line to be `ju would make it possible to observe whether thereis an singing taking place. Under certain con `tions, any suitableimpedances may be substituted R2 indicated in Figure 2.

dged and for the resistancesR, R1,

gana

In Figure 3 another Iautomatic process -for balancing the impedances hasbeen shownyobtained -b'ymeans of a cial separate self induction coil.This self-lnduction coil comed by means of resistances R13, R2., R32,R2l and these samel :windings are the eastern side' of the telephoneline andone side of amplifier transformer, and windings S1,a and Sg areinserted between the western side of the line and the other side of`amplifier transformer, the windings being connected in such a manner asto produce noiuxwhen the eastern and western line currents are equal.Under these no-flux conditions there wlll be but a negligible voltageacross each of the-windings Sw S2., S.3a andSu, 'and hence practicallyno current through the damping resistances R1., R2., Ran, and R,a inshunt thereto. But as. soon as the eastern and western sides of the lineare traversed by current ofv different intensities there is\a resultingmagnetic iiux and cur rents How in the resistances R1., Rz., R3. andR4., and these currents tend to reestablish symmetry. With regard tothis figure it is to be noted that unlike the receding figures thewindings concerned orm no part of the transformer, but constitute ratherafspecial selfinduction coil. v'

Another arrangement is illustrated in Figure 4. In this arrangement thetransformer 'I3 is divided into independent transformers, so constructedas only to take very littlemagnctizing current. The equality of thecurrents tends this time also 'to be produced automatically on theeastern and Iwestern sides of the line.

In Figure 1 a two-lamp amplifying arrangement has been shown, but theinvention extends of course to cases inwliich only a single relay lampis employed, or any number of relay lamps.

The invention may'beapplied also to circuit arrangements in which theamplifying system-is supplied with current in series on the telephoneline instead' of being fed in shunt of this line as' shown in Fig. 1,and in accordance with which the amplified current has its exit in shuntof the telephone line, instead of having its exit in series as shown inrl/lie patent referred to above discloses an arrangement of telephoneamplifiers fondeforining the voice, the effect of which is counter-actedby the deformation-caused by the telephone line whereby the use oflinesi. `without Pupin coils is feasible.

Preferably, such amplifiers will be constructcd with transformerssupplied with a strong magnetizing current (e. g. air gap transformers).and the primary or secondary windings of which are shunted by capacitiesadapted to compensate the magnetizing current for the highest frequencyof the telephone currents. l

Under these conditions, the harmonics will be automatically reinforced.

For the same purpose, it is advisable to reduce the magnetic leakagesbetween the primary and secondary windings by locating ,line as shown inFig. 1".

the primary inthe centre of the secondary or vlcel versa. The weakeningedect of the leakage inductances will be felt the more, the

higher the frequency.

Amplifiers may be distributed over suiivciently long lines and dependingon their connectin with the line, these amplifiers will either increasethe resistance of the line, or

compensate the losses.- In this manner, the

with the interposition of transformers, in a manner to reduce thecrackling sound of the The middle points of the windings of thesetransformers may be connected together and the potential of this commonconnection may be defined to geduce the probability of arcing.

Having described my invention, what I claim is:

1. In an amplifying system, two sections of' telephone conductors,a-transformer having a primary winding` and secondary windings, saidsecondary vwindings telephonically connecting the sectionsl oftelephoneclconductors, amplifying means having an input circuit and anout ut circuit, said input circuit being connecte to' pointsintermediate the ends of said rsecondary windings, said primary windingfunctioning to `connect induc tively said outputcircuit to'saidsecondary windings, and resistances connected across said windings tocompensatel automatically for differences -`in impedance between saidsections.

2. In an Aamplifying system,'two sections of telephone conductors, atransformer having a primary winding and secondary Windings, saidsecondary windings telephonically connecting the sections of telephoneconductors, amplifying means having an input circuit and an out utcircuit, said input circuit being connecte to points intermediate theends of said secondary windings, said primary winding functioning toconnect inductively said output circuit to said secondary windings, andmeans including two resistances to compensate automatically fordifferences in impedance between said sections, one of said resistancesbeing connected between one side of one section and the remote side ofthe other section, and the other resistance being connected between theother two sides of said sections.

3. In an amplifying system, two sections of telephone conductors, atransformer having a primary winding and secondary windings, saidsecondary windings telephonically connecting the sections of telephoneconductors, amplifying means having an input circuit and an outputcircuit, said input circuit being connected to points intermediate theends of said secondary windings, said prinemen g marly to connectnducmote termini] of the other secondary windti've said output circuitto saldrsecondenry ing and the other resistance being connected vn gs,and means including resistencias between the other terminals of -saidsecondl0 v for compensating eutomptcslly for diersry wmdmgs and sresistance connected in 5 ences in impedences between seid sections,shunt of se'ld primary winding. oneresistsnce being connected betweenthe terminal of one swondery winding and e re- HABIUS LATOUR.

